Avalanche Forecast
Issued: Dec 2nd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
zryan,
Avalanche Canada
Careful snowpack evaluation is required to manage a late October facet/crust layer that has shown reactivity in a recent size 2.5 skier-remote avalanche. Be aware that if triggered, wind slab avalanches may step down to this deeper layer resulting in larger avalanches.
Summary
Confidence
Weather Forecast
Thursday night: Flurries, up to 10 cm. Moderate to strong southerly winds. Alpine temperatures around -15 C.
Friday: Light flurries. Moderate southeast winds, shifting southwest in the afternoon. Alpine temperatures drop to -20 C.
Saturday: Winds increasing to strong and shifting to the northwest. Alpine temperatures reach -25 C with light flurries throughout the day.
Sunday: Building high pressure will bring mainly clear skies. Light to moderate ridgetop winds from the west. Alpine temperatures around -20 C.
Avalanche Summary
On Tuesday, a size 2.5 skier-remote persistent slab was reported on the MIN (see report here). The avalanche was triggered from around 100m away, by a group of 5 riders on an east aspect at 1400m. The avalanche was suspected to have failed on an early-season facet/crust layer.
Lots of whumping and cracking have been reported across the region, which is most likely associated with an early-season shallow snowpack, wind slab formation, and a weak facet/crust layer at the base of the snowpack.
Thank you for the all informative and detailed Mountain Information Network reports! Remember that it is still early season, and we look forward to hearing more this weekend.
Snowpack Summary
Another 5-10 cm of new snow will add to last week's 30 cm of storm snow. This new snow will continue to be transported by moderate to strong southerly winds into wind slabs in the alpine and treeline.
A facet/crust layer can be found near the bottom of the snowpack. This layer has been reported as being reactive to human triggering in the past week, with a notable skier-remote avalanche on Tuesday.
Terrain and Travel
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Southerly winds and continued snowfall will form new wind slabs at the treeline and above. Cracking and whumping are an indication of wind slabs in the upper snowpack. Remember that if triggered, wind slabs have the potential to step down to deeper layers.
Aspects: North, North East, East, South East, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A persistent weak layer of facets over a crust near the bottom of the snowpack has been reported as being reactive to human triggers. Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 3rd, 2021 4:00PM
